This application proposes to support the continued activities of the Pathology Committee of the Childrens Cancer Study Group. The Committee is one of the principal standing committees of this clinical trials cooperative group, providing pathology expertise and leadership into the design and conduct of Group protocols, research utilization of Group pathology resources, and educational efforts of concern to pathologists. The Committee is responsible for quality control support of Group protocols and will provide diagnostic confirmation of all patients entered on solid tumor protocols. The pathology membership, under the direction of the Pathology Steering Committee and assisted by the Pathology Center, will initiate, conduct and report research investigations utilyzing pathology and clinical material available on CCSG study patients. The Committee will be active in providing educational materials and programs to Group members, reporting current knowledge in pediatric tumor pathology, research results and pathology requirements of Group protocols. The Childrens Cancer Study Group is a national cooperative group of 30 primary and approximately 120 affiliate institutions. The Group conducts pediatric cancer clinical trials, employing a multidisciplinary approach to diagnosis and treatment. Group institutions care for approximately 60 percent of al pediatric cancer patients in the United States. This application requests support for the personnel of the Committee Pathology Center, located at Children's Hospital, Columbus, Ohio; for histopathology processing costs; for equipment; for travel needs of the Committee; and for other support costs explained in the application.